This changes cleans up some deprecated functions that were removed in
Qt6. Some are placed behind version ifdefs and others are replaced for
their non-deprecated Qt5 version.
This object should not always be created on startup. Instead, only load
it specifically when the user wants to load it.
This fixes a freeze some users were experiencing due to the text widget.
Unfortunately, it is not yet known how that freeze occurred with the log
viewer, so for the time being do not load the log viewer object unless
explicitly created.